老年人和儿童膳食中锌生物利用率的研究以及锌营养状况评价指标的初探

Dietary reference intakes are the most fundamental science basis of nutrition science, the ruler of nutritional status evaluation, and the main basis of the food nutrients labels. Due to the lack of zinc bioavailability data of Chinese people, we had to reference the Western standards to draw up the current dietary reference intakes for zinc , iron and so on. However physiological characteristics and dietary pattern of our residents are different from Westerners, especially the main factors that affect zinc absorption in the diet were significantly different. Therefore, studying on the dietary zinc absorption and utilization in residents is the core content for developing Chinese DRIs. In current study，we will design representative diet according to recent national nutrition survey data ,and take the stable isotope labeled whole dietary method to study zinc bioavailability of the representative diet in the Chinese eldly and children. It will provide critical science basis for the development of zinc dietary reference intakes..In addition, lacking of sensitive and specific evaluating indicators for zinc nutrition is an important problem that need to be resolved in the field of nutrition science. In present study, we will carry out zinc supplement experiments in zinc deficiency people and collect biological samples from these people. Using proteomics technology to explore new indexes for evaluating zinc nutritional status will lay the foundation for the development of new detection targets or methods， and open up new areas of zinc nutrition research.

膳食营养素参考摄入量（DRIs）是营养科学最基础的科学依据，是评价营养状况的标尺，也是食品营养素标识的主要依据。由于缺乏国人研究资料，我国现行锌、铁等DRIs都是参考西方人的标准制订，而我国居民的生理学特点和膳食结构均与西方人有所不同，特别在膳食中影响锌吸收的主要因素方面有明显差异。因此，研究国人膳食锌吸收利用是制定符合我国DRIs的核心内容,本研究拟采用稳定同位素标记的全膳食法（金标准），根据近期全国营养调查数据设计代表性膳食，研究在此代表性膳食条件下老年人、儿童锌的吸收利用率，为制定锌的膳食参考摄入量提供关键科学依据。.此外，针对缺乏敏感的、特异的锌营养状况的评价指标这个营养领域亟待解决的重要科学问题，本研究将选择锌缺乏人群进行锌补充实验，收集从缺乏到正常的生物样本，利用蛋白组学技术从新的角度探讨评价锌营养状况的新指标，为发展新的检测靶标或方法奠定基础，开拓锌营养研究的新领域。

招募19名儿童和24名老年人，利用稳定性同位素单标技术（67Zn）进行膳食锌生物利用率的研究。稳定性同位素实验时每人早中晚餐各给予1mg67Zn，收集实验期间的粪便。热离子源质谱仪检测收集的粪便中锌稳定性同位素的比值并计算膳食锌的生物利用率。研究结果如下：儿童在平均摄入9.1mg膳食锌时吸收率为29.0±11.9%，老年人在平均摄入10.1mg膳食锌时吸收率为27.9±9.2%。.采用2010-2012年中国居民营养监测中6-12岁贫困农村儿童血清，根据其血锌含量分为三组：低锌组（427-645ppb）、中锌组（722-850ppb）、高锌组（1153-1694ppb），每组中每13人血清混和为1个样品，共9个样品，通过同位素标记相对和绝对定量技术分析发现了280个蛋白成分，组间进行单因素方差分析后得到11个差异蛋白，结合差异蛋白功能以及锌参与的生长发育、免疫、代谢调节等功能，初步认为5种蛋白可以作为评价个体锌营养状况的生物标志物。